As an example of an electric actuator, which rotates the output shaft, a technique, which is disclosed in the patent literature 1, is known.
In the electric actuator of the patent literature 1, a rotational speed of a rotational output, which is generated by an electric motor, is reduced through a speed reducing gear device of a parallel shaft type, and the rotation of the reduced rotational speed is conducted to the output shaft to drive the same. The speed reducing gear device includes intermediate shafts, which are parallel to the output shaft. The intermediate shafts are supported by a housing.
One end of the output shaft is rotatably supported by a bearing (hereinafter referred to as a housing-side bearing) that is placed between the housing and the output shaft.
Furthermore, the other end of the output shaft is rotatably supported by a bearing (hereinafter referred to as a cover-side bearing) that is placed between a cover and the output shaft.
In the electric actuator of the patent literature 1, the output shaft and the intermediate shafts are used to position the cover relative to the housing.
Therefore, at the time assembling the cover to the housing, it is not possible to control a gap between the cover-side bearing and the output shaft and a gap between the housing-side bearing and the output shaft. Thus, in such a case, the cover may possibly be assembled to the housing in a state where the gap is absent between the cover-side bearing and the output shaft and also between the housing-side bearing and the output shaft. Thereby, the cover may be fixed to the housing in a state where an excessively large load is applied to the output shaft.
In the state where the cover-side bearing is urged against the output shaft with the excessively large load, and the housing-side bearing is urged against the output shaft with the excessively large load, when the output shaft is rotated, damage, such as wearing, may possibly occur at the cover-side bearing, the housing-side bearing and the output shaft. Specifically, malfunctioning of the electric actuator and generation of a noise may possibly occur.